全文获取类型
收费全文 | 19307篇 |
免费 | 1645篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 207篇 |
儿科学 | 655篇 |
妇产科学 | 422篇 |
基础医学 | 3010篇 |
口腔科学 | 387篇 |
临床医学 | 2115篇 |
内科学 | 4032篇 |
皮肤病学 | 316篇 |
神经病学 | 1652篇 |
特种医学 | 567篇 |
外国民族医学 | 1篇 |
外科学 | 2413篇 |
综合类 | 128篇 |
一般理论 | 19篇 |
预防医学 | 1809篇 |
眼科学 | 449篇 |
药学 | 1456篇 |
中国医学 | 22篇 |
肿瘤学 | 1330篇 |
出版年
2023年 | 138篇 |
2022年 | 191篇 |
2021年 | 407篇 |
2020年 | 306篇 |
2019年 | 451篇 |
2018年 | 449篇 |
2017年 | 412篇 |
2016年 | 473篇 |
2015年 | 463篇 |
2014年 | 617篇 |
2013年 | 807篇 |
2012年 | 1115篇 |
2011年 | 1067篇 |
2010年 | 602篇 |
2009年 | 538篇 |
2008年 | 896篇 |
2007年 | 915篇 |
2006年 | 859篇 |
2005年 | 817篇 |
2004年 | 861篇 |
2003年 | 759篇 |
2002年 | 697篇 |
2001年 | 448篇 |
2000年 | 479篇 |
1999年 | 434篇 |
1998年 | 214篇 |
1997年 | 182篇 |
1996年 | 175篇 |
1995年 | 168篇 |
1994年 | 162篇 |
1993年 | 154篇 |
1992年 | 317篇 |
1991年 | 343篇 |
1990年 | 343篇 |
1989年 | 350篇 |
1988年 | 264篇 |
1987年 | 283篇 |
1986年 | 240篇 |
1985年 | 291篇 |
1984年 | 197篇 |
1983年 | 174篇 |
1982年 | 140篇 |
1981年 | 107篇 |
1980年 | 99篇 |
1979年 | 170篇 |
1978年 | 131篇 |
1977年 | 111篇 |
1975年 | 100篇 |
1974年 | 118篇 |
1973年 | 109篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Christian Holm Hansen Shelley Lees Saidi Kapiga Janet Seeley Tony Barnett 《Global public health》2020,15(3):402-413
ABSTRACTMeasuring hope reliably and accurately remains an important research objective, not least in less prosperous settings where ‘holding on to hope’ may be critically important in the struggle against adverse life conditions. The State Hope Scale was designed for use in the US. Despite reported application in diverse cultures and using translations the scale has not been extensively validated outside US populations. This study contributes to a larger project exploring the measurement of hope and provides a critique of Snyder’s scale as used in a Tanzanian female population of 1021 urban microfinance participants. We evaluate the scale’s validity through assessment of the empirical distribution of scores, item response profiles, internal consistency and discriminatory ability. Participants mostly scored very high and many reached very near the maximum attainable score. Hardly any endorsed the negative half of the response scale. Several problems are discussed including poor discrimination and strong evidence of acquiescence response bias. We also found little association of the scale scores with hypothesised correlates of hope. Future improvements on the measurement of hope are recommended, especially in studies outside the narrow Western context in which the scale was devised. 相似文献
2.
Non‐melanoma skin cancer frequently results from chronic exposure to ultraviolet (UV) irradiation. UV‐induced DNA damage activates cell cycle arrest checkpoints through degradation of the cyclin‐dependent kinase activators, the cell division cycle 25 (CDC25) phosphatases. We previously reported increased CDC25A in nonmelanoma skin cancer, but CDC25B and CDC25C had not been previously examined. Consequently, we hypothesized that increased expression of CDC25B and CDC25C increases tumor cell proliferation and skin tumor growth. We found that CDC25B and CDC25C were increased in mouse and human skin cancers. CDC25B was primarily cytoplasmic in skin and skin tumors and was significantly increased in the squamous cell carcinoma (SCC), while CDC25C was mostly nuclear in the skin, with an increased cytoplasmic signal in the premalignant and malignant tumors. Surprisingly, forced expression of CDC25B or CDC25C in cultured SCC cells did not affect proliferation, but instead suppressed apoptosis, while CDC25C silencing increased apoptosis without impacting proliferation. Targeting CDC25C to the nucleus via mutation of its nuclear export sequence, however, increased proliferation in SCC cells. Overexpression of CDC25C in the nuclear compartment did not hinder the ability of CDC25C to suppress apoptosis, neither did mutation of sites necessary for its interaction with 14‐3‐3 proteins. Analysis of apoptotic signaling pathways revealed that CDC25C increased activating phosphorylation of Akt on Ser473, increased inhibitory phosphorylation of proapoptotic BAD on Ser136, and increased the survival protein Survivin. Silencing of CDC25C significantly reduced Survivin levels. Taken together, these data suggest that increased expression of CDC25B or CDC25C are mechanisms by which skin cancers evade apoptotic cell death. 相似文献
3.
4.
5.
Background
Hospital episode statistics (HES) is a UK national database for the National Health Service (NHS), now available online. The purpose of this study was to observe trends in ophthalmic operations performed during the period from 1998 to 2004, using this data. 相似文献6.
Clinical versus ultrasonographic evaluation of scrotal disorders 总被引:1,自引:0,他引:1
B Kromann-Andersen L B Hansen P N Larsen K Lawetz P Lynge D Lysen S P Nielsen K H Stockholm P Foged 《British journal of urology》1988,61(4):350-353
Clinical and ultrasonographic examinations of scrotal disorders were compared in 166 patients in order to determine their ability to distinguish between those diseases requiring surgery and those requiring clinical follow-up only. Ultrasound examinations were efficient in discriminating between normal and pathological findings. Extra-testicular lesions were readily differentiated from testicular ones. Although both clinical and ultrasonographic examinations had high sensitivity (90%) in detecting testicular cancer, the number of false positive findings was smaller after ultrasound examination. This gave a predictive value of a positive test of 53% after ultrasound examination but only 33% after clinical examination. Ultrasound examination may, therefore, reduce the number of surgical explorations in the scrotum and should be performed in patients with suspected testicular pathology based on history and palpatory findings. 相似文献
7.
Thirty-nine primary surgical cases for correction of congenital aural atresia were reviewed for complications and long-term hearing results. Hearing averages of 25 dB for mild atresia, 40 dB for moderate atresia, and 46 dB for severe atresia were obtained. Serviceable hearing was achieved in 64% of the cases. The two most frequent complications were stenosis and recurrent infections of the cavity and canal skin, with an incidence of 33% and 31%, respectively. Use of split-thickness instead of full-thickness skin graft was associated with fewer complications. The goal of this review is also to share the experience of the senior author in the management of this complex problem. 相似文献
8.
9.
Lucy Yardley David Papo Adolfo Bronstein Michael Gresty Mark Gardner Nilli Lavie Linda Luxon 《Neuropsychologia》2002,40(4):373-383
The aim of this series of experiments was to determine whether attention is normally required for continuously processing vestibular information concerning orientation, or is required only when orientation is disrupted (eg by vestibular dysfunction or by conflicting visual and vestibular orientation cues). In the first two studies, healthy subjects were passively oscillated, and indicated when they perceived they were passing through their starting position. There was only weak evidence for interference between performance on this 'continuous orientation monitoring task' and on concurrent mental tasks. However, a third study showed that when patients with vestibular imbalance carried out the continuous orientation monitoring task their performance on a concurrent mental arithmetic task was substantially impaired. This dual task interference was correlated with inaccuracy in judging orientation on the continuous orientation monitoring task, which in turn correlated with severity of recent vestibular symptomatology (assessed by questionnaire). In a fourth experiment, disorientation was induced in healthy subjects by rotating the visual field about the line of sight. Bidirectional interference was observed between monitoring orientation (assessed by accuracy in setting a rod to the perceived vertical) and performance of an arithmetic task. Dual task interference was correlated with baseline levels of disorientation induced by the visual field, as indicated by inaccuracy in judging the visual vertical. These findings suggest that monitoring orientation makes significant demands upon cortical processing resources when disorientation is induced, whether the disorientation results from deficient sensory functioning or from ambiguous perceptual information. 相似文献
10.
P.J. Hansen P. Soto . 《American journal of reproductive immunology (New York, N.Y. : 1989)》2002,48(3):150-150
Increased peripheral NK cells in aborting women are considered as a predictor of immunological miscarriages. Here, we investigated the diagnostic value of the NK count at the time of abortion. Peripheral NK cells were counted by flow cytometry in 44 women undergoing therapeutic termination of first trimester missed pregnancy (A = 24) or elective abortion (B = 20). Histology of the extracted material was performed and immunological lesions (villitis, intervillositis, vascular thrombosis, increased fibrinoid necrosis) were recorded. Twenty first trimester pregnant women (C1) and 20 nonpregnant women (C2) served as controls. In 20 women of groups A and B (A1 = 10, B2 = 10) count was repeated after 5 days. At abortion time, the NK percentage and number did not differ between groups A and B (18.18%, 360 versus 15.61%, 374), but there was a statistically significant difference between A and C1 (18.18% versus 13.6%, P < 0.03). When histology negative (11) and positive (8) cases were excluded from groups A and B, respectively, NKs were slightly higher in group A (18.18–19.76%) and significantly lower in B (15.61–13.07%, P < 0.05). At the time of second count, aborters' NKs decreased (A1 = 16.64 versus 13.6 and 10.6 in groups C1 and C2 –P = 0.01, respectively). In group B, NK percentage was equal to that of nonpregnant women (10.94 versus 10.6). At the time of abortions, NKs increase only in cases of immune‐mediated miscarriages. Their – in time – count may contribute to the diagnosis of immmunological abortions. 相似文献